One Colorado’s most steadfast, most unwavering, most uncompromising politicians is going back on his word.

Tom Tancredo is welching on weed.

During the campaign for Amendment 64 — which legalized marijuana use in Colorado and which Tancredo supported but didn’t think would win — the former congressman made a bet with a documentary filmmaker that he would smoke a joint with the filmmaker if the measure passed. It did and, as recently as last week, Tancredo said he planned to honor his bet.

But then came the joint juke. The bong-hit backtrack. The pot flip-flop.

Opponents of a measure to legalize limited possession of marijuana are hitting back, after a Denver Post poll showed the measure leading with 51 percent support.

Amendment 64 would legalize possession of up to an ounce of marijuana for adults and allow for marijuana to be sold in specialty retail stores, which cities could ban. The Post’s poll is the first time an independent poll has shown the measure above 50 percent.

“We have seen a tidal wave of out-of-state money trying to influence the outcome of our election and seeking to use Colorado as test case for a national pro-pot agenda,” Roger Sherman, the campaign director for No on 64, said in a statement. “We always knew it would be an uphill battle to fully inform Coloradans about this dangerous, deceptive amendment to our state constitution. But we believe voters are smart enough to understand why Amendment 64 is wrong for Colorado and will vote No.”

Sherman took issue with the poll’s language, which said the measure would “decriminalize” marijuana.

“By legalizing recreational marijuana, Amendment 64 clearly would expand access to kids,” Sherman said. “It will lead to a significant increase in the number of crashes and deaths due to people who are driving under the influence of marijuana. It poses enormous liability risks to employers. It puts Colorado in direct conflict with federal law, inviting a tangle of lawsuits, which will cost taxpayer money.”

Supporters of the measure, meanwhile, said in a statement the poll shows voters have thoroughly considered the amendment.

“Coloradans are ready to end the failed policy of marijuana prohibition and replace it with a more sensible, evidence-based approach,” said Betty Aldworth, a spokeswoman for the Campaign to Regulate Marijuana Like Alcohol, the group behind the measure. “Amendment 64 proposes just that. By regulating marijuana like alcohol we can redirect our limited law enforcement resources toward tackling violent crime, generate millions of dollars in tax revenue, control a currently uncontrolled market, and stop criminalizing adults simply for choosing a substance that is objectively safer than alcohol.”

The Campaign to Regulate Marijuana Like Alcohol is running a television ad on Friday with a Mother’s Day theme, according to the campaign.

The ad in support of Amendment 64, which would go to voters on Election Day, features a young woman writing an e-mail to her mother suggesting it’s high time they talk about her marijuana use. The young woman explains that marijuana use is, in her experience, safer and more healthy than the drinking she did in college.

The ad is set to run during NBC’s “The Today Show,” “Ellen” and the Mother’s Day episode of “The Doctors,” according to the presser.

“Our goal with the ad is to start a conversation — and encourage others to start their own conversations — about marijuana,” Betty Aldworth, the advocacy director for the campaign, said in the presser.

Tvert added that Colorado is a much different state than California and credited his group’s efforts with helping convince many people that marijuana is a safer drug than alcohol. Additionally, Los Angeles banned almost all medical marijuana dispensaries, while Denver grandfathered in approximately 200 medical marijuana centers.

“The most important thing is that Colorado isn’t California,” Tvert said. “It’s a different political climate, also has a different climate in regards to marijuana.”

Joey Bunch has been a reporter for 28 years, including the last 12 at The Denver Post. For various newspapers he has covered the environment, water issues, politics, civil rights, sports and the casino industry.